As an example of an adjustment member in a grille device of a vehicle, a movable fin is provided to adjust the amount of air intake into a radiator so as to maintain a cooling temperature by the radiator within a predetermined temperature range, and also adjust the amount of air intake into an engine room through the radiator so as to adjust the aerodynamic characteristics of the vehicle.
The movable fin is provided in an air intake path which takes in air from the front of the vehicle into the radiator to be movable between a block position for blocking the intake of air to the radiator and a permission position for permitting the intake of air to the radiator.
The grille device for a vehicle is provided with a grille controller that controls the opening and closing of the grille by moving the movable fin between the block position and the permission position by the operation of the motor controller.
The controlling of the opening and closing of the grille adjusts the amount of air intake into the radiator so as to maintain the cooling temperature by the radiator within the predetermined temperature range, and adjusts the amount of air intake into the engine room through the radiator so that the aerodynamic characteristics, such as desired air resistance, lift force, down force, or the like, can be provided to the vehicle.
The related-art controlling of the opening and closing of the grille starts when the vehicle starts traveling after the engine is started by a turning-on operation of an ignition switch, and ends when the engine is stopped by a turning-off operation of the ignition switch (for example, JP2008-6855A).
That is, during a time period from a time when the engine is started to a time when the vehicle starts traveling, the controlling of the opening and closing of the grille is not performed.
If the controlling of the opening and closing of the grille ends, and if the movable fin is in the block position, during the time period from the time when the engine is started to the time when the vehicle starts traveling, the controlling of the opening and closing of the grille might be not performed. Accordingly, in order to prevent overheating of the engine during this time period, an end process for moving the movable fin to the permission position is performed after the end of the controlling of the opening and closing of the grille.
After the end of the controlling of the opening and closing of the grille, the engine is stopped, and therefore, power generation by an electric generator is not performed. Accordingly, if an output voltage of a battery is lower than a startup voltage of the electric motor for moving the movable fin, the movable fin could not be moved to the permission position even though the electric motor is turned on in the end process.
Accordingly, when the movable fin is stopped in the block position at the end of the controlling of the opening and closing of the grille, and also the output voltage of the battery is lower than the startup voltage of the electric motor for moving the movable fin, the overheating of the engine could not be prevented during the time period from a time when the engine is started at a next time to a time when the vehicle starts traveling.
Also, when the power generation capability of the electric generator is deteriorated, the battery could not be charged sufficiently. Therefore, if the output voltage of the battery is lower than the startup voltage of the electric motor during the execution of the controlling of the opening and closing of the grille, the movable fin could not be moved even though the electric motor is turned on.
Accordingly, when the movable fin is stopped in the block position during the execution of the controlling of the opening and closing of the grille, i.e. during the traveling of the vehicle, and when the output voltage of the battery is lower than the startup voltage of the electric motor for moving the movable fin due to the deterioration of the power generation capability of the electric generator, the overheating of the engine could not be prevented.
Further, if the output voltage of the battery is abnormally heightened during the execution of the controlling of the opening and closing of the grille, a negative influence might be caused on the normal control operation of the motor controller or the grille controller which are operated by the electric power from the battery.
In this case, the control operation for moving the movable fin, which is stopped in the block position, to the permission position is not normally performed, and therefore, the engine could be overheated.
A need thus exists for a grille device for a vehicle which is not susceptible to the drawback mentioned above.